Dynamic Imaging of Aortic Pathologies: Review of Clinical Applications and Imaging Protocols

The past decade has seen significant advances in dynamic imaging of the aorta. Today's vascular surgeons have the opportunity to choose from a wide array of imaging modalities to evaluate different aortic pathologies. While vascular ultrasound and aortography are considered to be the bread and butter imaging modalities, newer dynamic imaging techniques provide time-resolved information in various aortic pathologies. However, despite growing evidence of their advantages in the literature, they have not been routinely adopted. In order to understand the role of these emerging modalities, one must understand their principles, advantages, and limitations in the context of various clinical scenarios. In this review, we provide an overview of dynamic imaging techniques for aortic pathologies and describe various dynamic computed tomography and magnetic resonance imaging protocols, clinical applications, and potential future directions.

Endovascular retrieval of a fractured Optease inferior vena cava filter using endobronchial forceps and intraoperative cone-beam computed tomography guidance

Endovascular retrieval of fractured inferior vena cava (IVC) filters after the manufacturer recommended indwelling time can be challenging and require advanced retrieval techniques. We describe an endovascular retrieval technique of a fractured Optease IVC filter in a 57-year-old woman using endobronchial forceps and intraoperative cone-beam computed tomography guidance. Following incomplete filter retrieval, the location and orientation of fractured strut was confirmed by cone-beam computed tomography venography. The embedded filter fragment was then successfully removed using endobronchial forceps via a transjugular venous approach. In the present report, we highlight the additional value of intraoperative cross-sectional imaging, in conjunction with advanced endovascular techniques, for retrieval of challenging IVC filters.

Image Guidance Techniques and Treatment Approach Optimization in the Management of Type-II Endoleak After Endovascular Aortic Aneurysm Repair

BACKGROUND

Over the past 3 decades endovascular aortic aneurysm repair emerged as the primary approach for abdominal aortic aneurysm management, however the occurrence of endoleak following endograft implantation imposes a high toll on patients and hospitals alike. The early diagnosis and appropriate treatment of endoleaks is associated with better outcomes, which calls for more advanced imaging and a standardized approach for endoleak diagnosis and management following endovascular aortic aneurysm repair. Although conventional strategy with non-targeted deployment of coils and embolic material in the aneurysm sac is considered to be the standard approach in many hospitals, it may not prove to be a viable option, given that it affects any further follow-up imaging in the event of sub-optimal therapy and consequent recurrence.

METHODS

Based on our tertiary aortic referral center experience we summarize and describe strategies for optimal selection of various treatment approaches for Type-II Endoleak management including endovascular, percutaneous and laparoscopic approaches with particular focus on intraoperative image guidance techniques.

RESULTS

After failed conventional endovascular embolization attempt we recommend specific complex type II endoleak management approaches based on the location of the endoleak within the aneurysm sac along the x, y and z axis. A transabdominal or laparoscopic approach enable treatment in endoleaks located in the anterior portion of the sac. Endoleaks in the posterior portion of the sac could be treated using the transcaval or the translumbar approach, depending on whether the endoleak is situated on the left or the right side. Alternative strategies should be considered if patient anatomy does not allow for either transcaval or translumbar approach. The transgraft technique is reserved for endoleaks located in the cranial portion of the sac, while the perigraft approach could present a means of treatment for endoleaks situated in the caudal portion of the aneurysm sac.

CONCLUSION

We encourage establishing a patient specific treatment plan in accordance with individual anatomy based on cross sectional imaging modality (time resolved dynamic imaging in selected cases) and intraoperative image guidance to provide a safe and accurate endoleak localization and embolization for patients undergoing type II endoleak treatment.

Emerging Applications for Computer Vision and Artificial Intelligence in Management of the Cardiovascular Patient

Artificial intelligence and telemedicine promise to reshape patient care to an unprecedented extent, leading to a safer and more sustainable work environment and improved patient care. In this article, we summarize how these emerging technologies can be used in the care of cardiovascular patients in such ways as fall detection and prevention, virtual nursing, remote case support, automation of instrument counts in the operating room, and efficiency optimization in the cardiovascular suite.

Employing magnetic resonance histology for precision chronic limb-threatening ischemia treatment planning

OBJECTIVE

Recent randomized controlled trials have demonstrated a notable prevalence of immediate technical failures in percutaneous vascular interventions (PVIs) for complex arterial lesions associated with chronic limb-threatening ischemia. Current imaging modalities present inherent limitations in identifying these lesions, making it challenging to determine the most suitable candidates for PVI. We present a novel preprocedural magnetic resonance imaging (MRI) histology protocol for identifying lesions that might present a higher rate of immediate and midterm PVI failure.

METHODS

We enrolled 22 patients (13 females, average age 65.8 ± 9.72 years) scheduled for PVI were prospectively and underwent 3T MRI using ultrashort echo time and steady-state free precession contrasts to characterize target lesions before PVI. Lesions were scored as hard if >50% of the lumen was occluded by hard components (calcium/dense collagen) on MRI in the hardest cross-section. Two readers evaluated MRI datasets. Trans-Atlantic Inter-Society Consensus Document on Management of Peripheral Arterial Disease (TASC)/Global Limb Anatomic Staging System (GLASS)/Wound, Ischemia and Foot infection scoring was performed based on intraprocedural angiograms and chart review. The relationship between MRI scoring, TASC/GLASS scoring, and procedural outcomes was investigated using univariate analysis. Midterm follow-up (revascularization and amputation rates) was recorded at 3 and 6 months after the intervention.

RESULTS

Our cohort of 22 patients yielded 40 target lesions. Five lesions were excluded (two for nondiagnostic image quality; three PVIs were ultimately diagnostic only). Six lesions (17%) were scored as hard. MRI-scored hard lesions had a higher proportion of immediate technical failure (hard vs soft 83% [5/6] vs 3% [1/29]; P < .001). Hard vs soft MRI scoring was the only factor significantly associated with immediate PVI technical success (P < .001), as opposed to TASC/GLASS scoring. Both at 3 months and 6 months after PVI, the reintervention rate was significantly higher among those lesions which were scored hard on MRI (3 months hard, 80% vs soft, 16% [P =.011]; 6 months hard, 80% vs soft, 27%; P = .047).

CONCLUSIONS

MRI histology could be a valuable tool for optimizing PVI patient selection and treatment strategies.

Retrospective Comparison of Stiff Wire-Based 2D3D, Traditional 3D3D Image Fusion, and Non-Image Fusion Techniques and Their Role in Thoracic Aortic Endovascular Repair

Objective: The aim of this study was to compare the outcomes of stiff wire-based 2D3D, 3D3D image fusion (IF), and non-image fusion techniques for simple zone 2 and zone 3 TEVAR cases in terms of radiation exposure, contrast dose, and fusion and projection accuracy. Methods: A single-center retrospective observational study was conducted based on data gathered from patients who underwent TEVAR between 2016 and 2023 at our tertiary aortic referral center. Those who underwent Z2 and Z3 TEVAR during the indicated period were included. The dose area product and number of DSAs were considered as primary outcomes, while projection accuracy and image fusion accuracy were considered as secondary outcomes. Results: A total of 79 patient were included. They were allocated to non-image fusion (NIF, n = 40), 2D3D IF (n = 14), and 3D3D IF (n = 25) groups. DAP was significantly lower both in the NIF [1542.75 µGym2 (751.72-3351.25 µGym2), p = 0.011] and 2D3D IF [1320.1 µGym2 (858.57-2572.07 µGym2), p = 0.013 groups compared to the 3D3D [2758.61 µGym2 (2074.73-4772.9 µGym2)] cohort. In the Z3 subgroup, DAP was significantly lower in the 2D3D IF group compared to the 3D3D IF group [(1270.84 µGym2 (860.56-2144.69 µGym2) vs. 2735.76 µGym2 (1583.86-5077.23 µGym2), p = 0.044]. 2D3D image fusion was associated with a significantly lower number of pre-deployment angiographies compared to NIF [1 (1-1) vs. 2 (1-3), p = 0.031], which we used as a surrogate for contrast dose. Conclusions: The entire study population analysis showed a significantly lower DAP with 2D3D IF compared to 3D3D IF, while there was no significant difference compared to NIF. It seems that stiff wire-based 2D3D IF does not cost in terms of DAP compared to NIF, while it is more favorable compared to 3D3D IF. Additionally, simple Z3 TEVAR cases might be improved by implementing the stiff wire-based 2D3D technique as a result of decreased DAP compared to 3D3D IF and decreased contrast dose compared to NIF.

Houston Methodist Ruptured Abdominal Aortic Aneurysm Guidelines

Ruptured abdominal aortic aneurysm (RAAA) is an acute aortic condition that requires emergent intervention and appropriate continuity of care to optimize patient outcomes. We describe the standardized RAAA protocol at the Houston Methodist Hospital Acute Aortic Treatment Center, developed to navigate critical patient transfer periods safely and efficiently, make crucial decisions about surgical intervention, and clearly communicate these plans with other care team providers. Our workflow is organized into five phases: prehospital, preoperative, intraoperative, postoperative, and post-discharge. We identify the transfer center, anesthesia, operating room nursing staff, surgeons, and intensive care unit as key entities of our acute aortic pathology care team. This systematic protocol for the management of acute aortic emergencies such as RAAA identifies critical decision points, potential complications at each stage, and recommendations for best practice.

Cadaveric aortic aneurysm creation: A life-like model for training endovascular repair

The recent decline in RAAA incidence and the fast paced scenario with associated challenges regarding training calls for initiative for a better training environment to maximize learning. This led us to the creation of a pulsatile human cadaveric RAAA model. Fresh frozen cadaver was used to create RAAA with BioTissue in hybrid suite with ability to perform CBCTA for sizing. As a proof of concept, the model was used to perform REVAR with proximal CODA balloon control. The model proved to be feasible and we believe it is a better environment to train and gain adequate proficiency in RAAA management.

Cadaveric training model for the management of type B aortic dissection using thoracic endovascular aortic repair along with the PETTICOAT technique

This model gives residents and fellows practice in the surgical repair of a type B aortic dissection using thoracic endovascular aortic repair implantation by the Provisional Extension To Induce Complete Attachment (PETTICOAT) technique. A human cadaveric model was created to simulate the procedure. A Dacron graft was pulled into the aorta distal to the left subclavian artery using two glidewires. Imaging confirmed the creation of a second lumen by the graft positioned within the aorta to simulate an aortic dissection. The PETTICOAT technique was then implemented with the implantation of a Cook Dissection stent. This proved the method to be a reproducible means to train residents and fellows in type B aortic dissection repair using the PETTICOAT technique.